Cafés, burger vans and snack stalls throughout east London face spot checks on food hygiene and water quality, and Olympic arenas are being monitored to ensure there is no danger of legionnaires' disease.

The Games' swimming pools will be tested regularly for contamination by harmful organisms, and stretches of open water used for long-distance swimming, rowing, triathlon and sailing events will be sampled to ensure they are free of algae. Meanwhile, owners of small boats in the vicinity of the Weymouth sailing regatta will be warned not to release effluent into the water.

The National Health Service will also be attempting to inform overseas visitors how the NHS works, and the NHS Direct and 111 advice lines in particular.

Both the HPA and the London Olympics organising committee believe that outbreaks of diarrhoea or vomiting in the athlete's village are among the most likely risks to public health. This is where most of the 17,000 athletes and officials from 200 countries will be based.

According to the Department of Health: "The NHS has robust plans in place to prepare for any additional demands created by the 2012 Games. NHS organisations are working hard to ensure that the healthcare needs of local people are not compromised and that we also have high quality health services available to visitors."